Reflectivity (Z) and precipitation rate (R) can be related in form of a
power law \(Z=a \cdot R^b\). The parameters a and b depend
on the type of precipitation (i.e. drop size distribution and water
temperature). \(\omega radlib\) provides a couple of functions that
could be useful in this context.

The following example demonstrates the steps to convert from the common
unit dBZ (decibel of the reflectivity factor Z) to rainfall
intensity (in the unit of mm/h). This is an array of typical
reflectivity values (unit: dBZ)

The following example is based on observations of the DWD C-band radar
on mount Feldberg (SW-Germany). The figure shows a 15 minute
accumulation of rainfall which was produced from three consecutive radar
scans at 5 minute intervals between 17:30 and 17:45 on June 8, 2008.

The radar data are read using
wradlib.io.read_dx
function which returns an array of dBZ values and a metadata dictionary
(see also
Reading-DX-Data).
The conversion is carried out the same way as in the example above. The
plot is produced using the function
wradlib.vis.plot_ppi.

In [6]:

defread_data(dtimes):"""Helper function to read raw data for a list of datetimes <dtimes> """data=np.empty((len(dtimes),360,128))fori,dtimeinenumerate(dtimes):f=wrl.util.get_wradlib_data_file('dx/raa00-dx_10908-{0}-fbg---bin.gz'.format(dtime))data[i],attrs=wrl.io.read_dx(f)returndata